/*
 * Copyright (c) 2007, 2015, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */
/*
 * Copyright 2001-2004 The Apache Software Foundation.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/*
 * $Id: CompareGenerator.java,v 1.2.4.1 2005/09/05 11:08:02 pvedula Exp $
 */

package com.sun.org.apache.xalan.internal.xsltc.compiler.util;

import com.sun.org.apache.bcel.internal.generic.ACONST_NULL;
import com.sun.org.apache.bcel.internal.generic.ALOAD;
import com.sun.org.apache.bcel.internal.generic.ASTORE;
import com.sun.org.apache.bcel.internal.generic.ConstantPoolGen;
import com.sun.org.apache.bcel.internal.generic.ILOAD;
import com.sun.org.apache.bcel.internal.generic.ISTORE;
import com.sun.org.apache.bcel.internal.generic.Instruction;
import com.sun.org.apache.bcel.internal.generic.InstructionList;
import com.sun.org.apache.bcel.internal.generic.LocalVariableGen;
import com.sun.org.apache.bcel.internal.generic.Type;
import com.sun.org.apache.xalan.internal.xsltc.compiler.Constants;

/**
 * @author Jacek Ambroziak
 * @author Santiago Pericas-Geertsen
 */
public final class CompareGenerator extends MethodGenerator {

  private static int DOM_INDEX = 1;
  private static int CURRENT_INDEX = 2;
  private static int LEVEL_INDEX = 3;
  private static int TRANSLET_INDEX = 4;
  private static int LAST_INDEX = 5;
  private int ITERATOR_INDEX = 6;

  private final Instruction _iloadCurrent;
  private final Instruction _istoreCurrent;
  private final Instruction _aloadDom;
  private final Instruction _iloadLast;
  private final Instruction _aloadIterator;
  private final Instruction _astoreIterator;

  public CompareGenerator(int access_flags, Type return_type,
      Type[] arg_types, String[] arg_names,
      String method_name, String class_name,
      InstructionList il, ConstantPoolGen cp) {
    super(access_flags, return_type, arg_types, arg_names, method_name,
        class_name, il, cp);

    _iloadCurrent = new ILOAD(CURRENT_INDEX);
    _istoreCurrent = new ISTORE(CURRENT_INDEX);
    _aloadDom = new ALOAD(DOM_INDEX);
    _iloadLast = new ILOAD(LAST_INDEX);

    LocalVariableGen iterator =
        addLocalVariable("iterator",
            Util.getJCRefType(Constants.NODE_ITERATOR_SIG),
            null, null);
    ITERATOR_INDEX = iterator.getIndex();
    _aloadIterator = new ALOAD(ITERATOR_INDEX);
    _astoreIterator = new ASTORE(ITERATOR_INDEX);
    il.append(new ACONST_NULL());
    il.append(storeIterator());
  }

  public Instruction loadLastNode() {
    return _iloadLast;
  }

  public Instruction loadCurrentNode() {
    return _iloadCurrent;
  }

  public Instruction storeCurrentNode() {
    return _istoreCurrent;
  }

  public Instruction loadDOM() {
    return _aloadDom;
  }

  public int getHandlerIndex() {
    return INVALID_INDEX;           // not available
  }

  public int getIteratorIndex() {
    return INVALID_INDEX;
  }

  public Instruction storeIterator() {
    return _astoreIterator;
  }

  public Instruction loadIterator() {
    return _aloadIterator;
  }

  //??? may not be used anymore
  public int getLocalIndex(String name) {
    if (name.equals("current")) {
      return CURRENT_INDEX;
    }
    return super.getLocalIndex(name);
  }
}
